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Ever thought about ... ?

I was asked a series of interesting questions this week about fault protection and overload protection for a particular application. Some of these really make you think, and the physics doesn't always lead you where you think you'd go.


Dropping out of all this, was me pointing out something interesting which I wonder whether it's ever crossed the minds of contributors to this Forum ... so here goes.


Ever thought about what, in typical UK installations, protects the electronics in a plug-in [to a standard BS 1363-2 socket-outlet] phone charger / wall-wart type power converter against:

(a) Fault current (consider both cases of L-N and L-PE); and

(b) Overload current ?





Parents
  • HOWEVER this is NOT the case for BS1361, BS88, or BS 3036 rewireable fuses, with BS 3036 being perhaps the worst-case let-through.

    Interesting. Do you have numbers for BS 3036 fuses? (I (or rather Google) have failed to locate any so far).


    Given that the permitted Zs values for a rewireable are if anything a little higher than for either a BS88-3 (e.g. according to table 41.2) I would have though BS 3036 ones would have if anything slightly quicker disconnection times for the same current than an BS 88-3 and therefore (broadly) a lower I²t.


       - Andy.
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  • HOWEVER this is NOT the case for BS1361, BS88, or BS 3036 rewireable fuses, with BS 3036 being perhaps the worst-case let-through.

    Interesting. Do you have numbers for BS 3036 fuses? (I (or rather Google) have failed to locate any so far).


    Given that the permitted Zs values for a rewireable are if anything a little higher than for either a BS88-3 (e.g. according to table 41.2) I would have though BS 3036 ones would have if anything slightly quicker disconnection times for the same current than an BS 88-3 and therefore (broadly) a lower I²t.


       - Andy.
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